This invention relates to a lateral back support for use with a seat in order support the back. More specifically, it relates to vertically orientated side pads that help resist lateral forces encountered while cornering.
While driving through a curve in a car, the lateral forces act on the body and push it sideways. The hips stay relatively motionless because the occupant's weight pushing down creates sufficient friction between the seat bottom and the occupant, thereby resisting the sliding movement. However, the torso is leaning against the seat back at an angle, which only transmits a small fraction of the weight to the seat back so its ability to resist the lateral forces is limited. Therefore, during cornering, the torso is pushed sideways and the occupant will consequentially exert physical effort to resist these forces.
In order to provide lateral support for the torso during cornering, most modern automobiles are equipped with bucket seats that include side bolsters. The side bolsters are extensions of the seat back that project forward on both sides of the seat and make contact with the torso, normally from the ribcage on down. The face of the side bolster is typically at a 45 degree angle to the lateral direction of force, slightly more on sports cars and less on trucks and vans. This angle is suitable for everyday usage as it allows easy entry and exiting the seat. It also accommodates a wide variety of users of greatly varying torso widths.
On racing seats, the angle of the side bolster surface that is in contact with the torso is nearly perpendicular to the lateral direction of force. This angle effectively supports the torso while cornering as the driver has a flat surface to lean against. Because the torso is immobilized, the side bolsters feel as if they are pushing back against the torso. This force is felt as feedback from the car. This feedback is critical as it conveys the amount of lateral force acting on the vehicle. The driver uses this feedback information and other factors to determine the velocity through the corner.
The side bolsters on a bucket seat are disposed at an obtuse angle with respect to the seat back thereof, not perpendicular, thereby providing torso immobilization. During cornering, the torso can slip along the side bolster face. This sideways pivoting of the torso can be very distracting as the driver must exert attention and energy to resist this force. While on roads with many corners, this reoccurring struggle can cause fatigue, which can lead to an error in judgment, possibly causing an accident.
Drivers have developed many techniques to overcome the lack of lateral support in a bucket seat. Intuitively, the upper body leans in the direction of the corner while pressing the torso into the opposite side bolster. The legs are pressed outward against the interior of the car. A common instinctual reaction is to grab hard on the steering wheel. This reduces the ability to feel the subtle feedback forces from the steering wheel as it is clenched tight. Amateur racers will press the torso hard against the seat back to create more friction between the two surfaces. This technique requires much strength and diverts energy and attention away from driving.
Another technique engages the seat belt tensioner while the seat is at a rearward position and then is slid forward which makes the belt feel tighter. Four and five point racing harness seat belts can be used to reduce sideways movement in a bucket seat. The shoulder belts press the torso hard into the back of the seat. The contact forces are felt primarily on the front and rear of the torso, not the sides, so the perception of lateral forces is not as clearly as felt in a racing seat.
Even with all of the aforementioned techniques and equipment, the quantity and quality of feedback from a bucket seat is much less than compared to a racing seat with perpendicular side bolsters. For most driving enthusiasts, changing out the stock bucket seat for a racing seat is an expensive and complicated option. Most car owners do not want a racing seat for everyday driving, as it is not as comfortable as the stock seat.
Furthermore, racing seats are difficult to get into, as the user must enter and exit straight forward. In addition, the interior width needs to be tailored for the specific user to ensure a snug fit.
Bench seats were standard for most of the 20th Century. Bucket seats were initially developed for automobile racing and were gradually introduced to mass-market cars in the 1970s. The leg and side bolsters on a bucket seat provide surfaces for the driver to lean against and stop the sideways sliding of the body while cornering.
The prior art discloses several examples of side bolster enhancements intended for bench seats. For example, U.S. Pat. No. 1,673,433, entitled Auxiliary Seat Back, discloses a seat accessory designed to constrain the driver's lateral body movement. The standard bench seat provides negligible side support. This device provides some lateral support as the padding thickness increases away from the vertical centerline. The pads are fixed to the seat by a pair of straps extending up and over the top of the seat back, thereby attaching the device to the seat and controlling its vertical position thereof. But, this particular mounting orientation is undesirable as it prevents the user from adjusting the vertical position of the device.
U.S. Pat. No. 2,081,111, entitled Automobile Cushion, discloses a device that acts as a stabilizer keeping the driver rigidly in place while going around curves. The support structure is composed of a backing sheet with two vertical pads, which is placed on a bench seat. It is held in position by the force of the driver leaning against the back of the seat. The section view shows the profile of the pads, which are inadequate to resist strong lateral forces, as they would tend to deflect sideways. Also, the shape of the pads undesirably fails to follow the contour of the back and is in need of more refinement.
Additionally, U.S. Pat. No. 2,822,033, entitled Lateral Support for Humans on Flat Vehicle Seats, and U.S. Pat. No. 2,822,034, entitled Collapsible Lateral Back Support, disclose pads that attach to the bench seat by a wide strap that wraps around the seat. The pads themselves are removable and can be attached in various positions along the strap. The face of the pad is at a 45 degree angle so in effect, this invention converts a bench seat backrest into the upper portion of a bucket seat by adding side bolsters. The side bolstering provided by this device, however, is far from the optimum perpendicular angle necessary to resist the lateral forces.
U.S. Pat. No. 3,542,421, entitled Back Supports, discloses a device having two vertical pads mounted to a centrally located material sheet structure that controls the horizontal spacing and the vertical position. The pads are attached to the backing with Velcro®-style hook and loop tape so that they can be adjusted to many different positions. The device is held in position by extending the upper portion of the central material, which has a semi-rigid member, up and over the seat back, thereby hooking it onto seat. As with U.S. Pat. No. 2,822,033, the face of the pad that is in contact with the driver is angled so its ability to resist the lateral forces is limited.
Additionally, U.S. Pat. No. 5,769,498, entitled Detachable Vehicle Seat Bolster, discloses a detachable device having a wishbone configuration that mounts to a vehicle seat. The structure has rigid sides that project forward of the side bolsters on the existing seat and provide surfaces that the driver may lean against during cornering. The side members are thin, however, and are insufficiently rigid enough to resist strong cornering forces. Furthermore, the amount of padding seems minimal, if any. Another drawback is that the device must be attached to the seat with hardware, thereby limiting the degree of adjustability.
U.S. Pat. No. 6,019,428, entitled Seat Bolster Adjustment Assembly, discloses a device where the side support members are all composed in one unit that mounts in back of the seat. This device, however, is highly complex and difficult to use.
In another prior art reference, U.S. Pat. No. 6,951,367, entitled Vehicle Seat Pad, discloses a device having a cloth material that covers a bucket seat and additional side bolster pads attached thereto with Velcro®-style hook and loop tape so that they can be adjusted to many different positions. The Velcro® fasteners are not designed to withstand the lateral forces associated with cornering would likely peel-off under lateral loading.
U.S. Pat. No. 7,237,848, entitled Back and Internal Organ Supportive Belt, discloses a device for use by heavy equipment operators. The contact surfaces of the pads are at an angle which provides support to internal organs and the musculoskeletal system. This device reduces the normal downward direction of force, not as a support against lateral forces encounter while cornering.
WO 2002083453, entitled Comfort Accessory for Vehicle Seat discloses vertically oriented pads attached to a central member that hooks onto the top of the seat. In addition, an air-filled bladder supports the lumbar region. Moreover, the pad mounting is accomplished with Velcro®. The pads are composed of a high-density foam inner core, with an outside layer of lower-density foam for comfort. The shape of the pads, however, does not provide sufficient support under lateral loading.
In general, conventional back support devices typically include a vertical semi-rigid member acting as the anchor point of the pads. While cornering, the lateral forces push the torso against the pads. If the pads are attached adequately, then the forces are transferred to the vertical semi-rigid member. The vertical semi-rigid member is not mounted to the seat in a manner sufficient to withstand strong lateral forces. Thus, the vertical semi-rigid member is prone to slipping out of position. Of the prior art references mentioned herein, none are available in the auto accessories aftermarket. In fact, many are simple concepts on paper that do not appear to have been thoroughly tested with any many evolving prototypes. The more elaborate designs are overly complicated with many parts, making them expensive and evidently, commercially nonviable.
There are prior art references that disclose mechanical and pneumatic devices for increasing the side bolstering, but these devices are built into the seat. While seated, the angle of the side bolster face can be adjusted depending on the driving conditions by activating a switch. A typical situation occurs when more side support is needed navigating a mountain road with many sharp corners. This adjustability feature is included in many contemporary luxury and sports cars. Some high-end models have sensors that monitor the cornering forces and automatically adjust the side bolsters to support the driver. These devices, however, are complex and expensive.
The most common solution to increasing the lateral support of non-adjusting side bolsters in a stock bucket seat is replacing it with a racing seat. This is an expensive option and uncomfortable for everyday driving.
A racing seat belt system can be added to a bucket seat which holds the driver in place by pressing the torso hard into the back of the seat. However, the torso can still slide side to side as the belts press backwards and rely on increasing the friction between the back and the seat to reduce the pivoting, not contact with the side bolsters. The G-Force Racing Gear torso harness is a simple latitudinal strap that wraps around the back of the seat and front of the chest and presses in on the torso. This prevents the torso from forward movement but is not effective is resisting lateral forces.
A popular product in the sports car community is the CG-Lock, the structure and operation being substantially disclosed in U.S. Pat. No. 6,938,925, entitled Apparatus for Use on a Safety Belt System for Restraining the Movement of an Occupant or Child Seat. The CG-Lock made by Lap Belt Cinch, Inc. of 120 Cornwall Road, Harrogate Landenberg, Pa. 19350, makes the lap portion of a standard seat belt tight and unyielding. This is very effective in preventing the hips and lower body from sliding during cornering. However, it does not affect the upper body, which is still free to lean side to side.
Another product called the Angel Pad limits the movement of the lower body during cornering. This device is comprised of a pair of foam blocks joined together by a fabric bridging element. The foam blocks are positioned on the outside of the hips and held in place by the force of the hips pressing the blocks against the car structure. Like the CG-Lock, this offers no support for the upper body.
Lateral supports for other types of seats are available especially in the category of wheelchairs, where the user may not have the ability to resist lateral forces.
There exists, therefore, a significant need for a lateral back support that includes a pair of adjustable pads removably mountable to a seat and disposed generally perpendicular to seat back. The present invention fulfills these needs and provides further related advantages.